San Francisco’s Secret Home-Field Advantage
ATT Park, from behind home plate, at game time for a night game.
Justin Upton has hit the ground running in San Diego. His power stats have not suffered as much as you might expect, at least, as his isolated slugging (.194) and home runs per fly ball (16.7%) are right in line with career norms (.201 and 15.1%, respectively). When I asked him about hitting in San Diego, he shrugged it off. He also said something interesting about San Francisco’s park.
“The one thing I look for in a park is whether you see the ball well and Petco Park is a great place to see the ball,” Upton told me. “There are certain places where there are bright backgrounds or things like that. I’m all about seeing the ball, then I can square it up. More during day games. Most parks have done a great job of making sure the backdrops are good. But in some day games, in certain areas of the park, like in San Francisco, there’s the stands on both sides, where it can get a little bit bright.”
This sort of thing is tough to test. But let’s say that AT&T park was bright during the day. Presumably that would change the offensive numbers during the day, and since the home team might be more used to it, it would affect the away team’s numbers more.
Below is a table that shows a comparison of day-game scoring to night-game scoring since AT&T Park opened in 2000. We’re looking at scoring through eight innings, since the ninth inning offers problems of its own. What we’ve done here is divide day scoring by night scoring for both the home and away teams. Then we’ve subtracted the difference between home and away to get a crude home-field advantage with respect to day-game scoring divided by night-game scoring.
What you’ll see is that the Giants have scored more in day games than night games, but their opponents have scored about the same in day and night games. Given that temperature is a big component of offense, this alone gives a whiff of truth to what Upton is saying. But, if you sort this for the league, you’ll see that other parks have bigger day/night discrepancies.
| Team | Home Day% | Away Day% | Home-Away |
|---|---|---|---|
| Mets | 104.0% | 92.0% | 12.1% |
| Astros | 110.8% | 99.0% | 11.8% |
| Tigers | 102.0% | 90.9% | 11.1% |
| Braves | 112.8% | 102.0% | 10.8% |
| Angels | 99.0% | 88.2% | 10.8% |
| Nationals | 101.6% | 91.3% | 10.4% |
| Red Sox | 102.9% | 94.3% | 8.6% |
| White Sox | 100.4% | 92.0% | 8.4% |
| Cardinals | 99.4% | 94.2% | 5.3% |
| Reds | 100.6% | 95.4% | 5.2% |
| Padres | 110.8% | 106.1% | 4.7% |
| Cubs | 106.4% | 102.2% | 4.2% |
| Royals | 104.7% | 100.6% | 4.1% |
| Yankees | 106.9% | 102.8% | 4.1% |
| Blue Jays | 94.5% | 90.7% | 3.9% |
| Giants | 102.9% | 100.0% | 2.9% |
| Dodgers | 98.9% | 97.5% | 1.3% |
| Mariners | 99.8% | 98.5% | 1.3% |
| Marlins | 100.8% | 99.5% | 1.3% |
| Phillies | 106.7% | 107.5% | -0.8% |
| Rangers | 89.0% | 90.2% | -1.2% |
| Athletics | 99.5% | 102.7% | -3.2% |
| Rays | 90.8% | 94.0% | -3.2% |
| Rockies | 97.7% | 100.9% | -3.3% |
| Twins | 95.8% | 100.0% | -4.2% |
| Indians | 93.5% | 97.7% | -4.2% |
| Pirates | 93.8% | 99.5% | -5.7% |
| D-backs | 88.2% | 94.4% | -6.2% |
| Brewers | 91.5% | 108.0% | -16.5% |
| Orioles | 88.1% | 109.3% | -21.2% |
I asked Will Venable about the park as well, and he agreed with Upton and pointed out that this extends into night games as well.
“During batting practice, it’s really bright,” said Venable. “Those empty bleachers are so bright, and the sun is setting behind you, so the light is pointing right at those seats. It can happen some in the first inning, too. I’m glad when I’m not leading off here. These parks are so great and professional, it’s not that big a deal, but you do notice when something is only a tiny bit off.”
ATT Park minutes before visitor’s batting practice.
So now we switch it over to night games. What this table shows is the average first-inning score divided by the average (cumulative) eighth-inning score for the home and away teams. How much scoring is done in the first inning by the home and away squads in each park? Then we subtract the away from the home to find a “first-inning home-field advantage.” Look who’s first.
| Team | Home Score% | Away Score% | Home-Away |
|---|---|---|---|
| Giants | 16.50% | 12.88% | 3.615% |
| Brewers | 16.03% | 12.55% | 3.488% |
| Angels | 13.16% | 10.15% | 3.015% |
| Blue Jays | 13.19% | 10.69% | 2.503% |
| Cardinals | 14.98% | 12.54% | 2.444% |
| Braves | 14.64% | 12.38% | 2.257% |
| Yankees | 14.80% | 12.67% | 2.136% |
| D-backs | 14.97% | 12.99% | 1.974% |
| Red Sox | 13.73% | 12.14% | 1.591% |
| Marlins | 15.68% | 14.15% | 1.531% |
| Indians | 13.72% | 12.22% | 1.509% |
| White Sox | 13.74% | 12.26% | 1.471% |
| Phillies | 15.35% | 14.10% | 1.243% |
| Reds | 14.80% | 13.56% | 1.240% |
| Royals | 14.22% | 13.08% | 1.144% |
| Rangers | 12.25% | 11.63% | 0.624% |
| Padres | 14.48% | 13.96% | 0.524% |
| Orioles | 12.94% | 12.43% | 0.509% |
| Twins | 13.06% | 12.82% | 0.236% |
| Cubs | 13.50% | 13.29% | 0.207% |
| Dodgers | 15.59% | 15.41% | 0.181% |
| Pirates | 14.89% | 15.20% | -0.315% |
| Athletics | 12.65% | 13.04% | -0.390% |
| Mariners | 12.85% | 13.26% | -0.410% |
| Nationals | 14.09% | 14.59% | -0.497% |
| Astros | 14.57% | 15.33% | -0.763% |
| Rockies | 13.57% | 14.42% | -0.850% |
| Mets | 13.67% | 14.79% | -1.112% |
| Tigers | 12.61% | 14.11% | -1.492% |
| Rays | 11.44% | 13.63% | -2.188% |
So the Giants have the largest first-inning home-field advantage in baseball. They score many of their runs in the first inning — maybe because it’s warmer — while their opponents score a much smaller percentage of their runs in the first inning. Maybe because the center-field bleachers are bright.
One of the amazing things about baseball is how different each home park is. That also makes it hard to analyze home-field advantage, since the temperature, humidity, and wind patterns change from game to game, from year to year… and from inning to inning. The Giants probably didn’t plan to have this home-field advantage through their batting eye, and it may not amount to much in the grand scheme of things, but it’s still remarkable that they enjoy any advantage because of the materials used in building their center-field bleacher seats.
With a phone full of pictures of pitchers' fingers, strange beers, and his two toddler sons, Eno Sarris can be found at the ballpark or a brewery most days. Read him here, writing about the A's or Giants at The Athletic, or about beer at October. Follow him on Twitter @enosarris if you can handle the sandwiches and inanity.
It’s possible this otherwise excellently conceived article would be if anything even more compelling if the Giants actually had a winning record at home this season.
He says the advantage lasts only for the beginning of the game….
It’s also horse hooey.
Anything more than an empty declarative statement?
My antenna instantly perked up because it could represent part of the reason the dodgers win so little against a team that can barely remain at .500.
at home, sorry
Yes, they are like the reverse Rockies this year. Great hitters on the road, poor at home. The run differentials are night and day.
More evidence on how awful the Trop is. Good thing the Giants didn’t move there.
NOT!
Lineup construction (Bonds batting in 1st inning) is likely going to be the biggest driving factor for 1st inning vs 2-8 for teams.
I do think there are tougher parks to see in, I’m not certain how much the home team can adjust and get an advantage though. Like you said, tough to get at.
Interesting – think they could look at just the 1 – 3 batter in the 1st inning vs. the rest of the game?
Presumably this would even out over 15 years. At least there are more non-Bonds years than Bonds years in here.
I’ve always wondered if there was some sort of minor competitive advantage to them starting the games at 7:15.
But it’s probably just that they know their fans will be late.
If you’ve ever taken BART or Muni to a game, you’d forgive the fans for not being there exactly on time
I have never taken Munenori Kawasaki to a game, but I have to imagine that it would be the best baseball experience ever.
Especially if your team wins, in which case he’ll gently lay down on you.
Nonsense. I have taken BART to the ballpark many times and never once have I been late. It is very convenient, as it drops you off directly in front of the ballpark… unlike the T in Boston which is much less convenient.
Bart definitely does NOT drop you off directly in from of ATT Park. That is completely false.
All the stops are quite a walk from the park actually.
You’re going to have to let the rest of us in on where the secret AT&T BART stop is located…
Yeah — because it’s so hard to leave 5-10 minutes earlier to account for the always-late BART or MUNI. Truth is, Giants fans are too busy updating their Facebook profiles to make it to the game on time (or to pay attention to the game once they’re there).
Teams have various reasons for starting their games at odd times. Mariners evening games generally start at 7:10pm. I don’t think it’s a coincidence that the local ESPN radio affiliate that broadcasts their games is found at AM 710.
http://www.caltrain.com/schedules/weekdaytimetable.html
I’m guessing it’s because the #279 Caltrain (which is local in Santa Clara county, then expresses through San Mateo county and South SF) arrives at 7:04.
Nice analysis! This would make a lot of sense, because the Giants have generally have had a strong home advantage at AT&T, this season and start of 2000, notwithstanding.
However, what Venable said makes no sense at all to me, perhaps someone can explain it to me. He said the empty bleachers bother him visually, which makes sense during batting practice, but the Giants have been selling out their games for a long time now, and even when not selling out, been close to sell outs. There should be no empty bleachers to bother him during games, unless the fans in the bleachers regularly come late to the games, leaving them empty in the first inning.
Don’t how this would be testable, but many free agents have come to the Giants and talked about how they need a season to figure out how to hit in AT&T. Perhaps this first inning differentiator could be part of this phenomenon. I checked Pence and it was true for about two years in, then he started hitting poorly again (I tracked his hitting in each home series for a couple of seasons).
I’ve also been wondering what parallels there could be between the early 2000’s and the past few years. Most people haven’t noticed, but the park played as a pitcher’s park for a number of years early on, then turned into a neutral park for a while there, which I wondered if it was related to Bonds leaving, but then became a pitcher’s park again in recent years.
The only thing I could think of was temperature. Summers were pretty hot here in the early 2000’s (live in South Bay) then cooled for a while, but has been getting hotter in recent seasons. But that’s down here, whereas it is much more temperate where the ballpark is, and I can’t imagine that the heat would affect players that significantly there (especially to make it into a pitcher’s park, unless Venable’s comment about the sun on the bleacher seats, perhaps when the region is hotter, it does something to the sunlight to make it harder to see in the park? That is, it is not a bleacher seat issue, but a general visual issue due to the particular lighting that day from the sun?)
Look at the top picture. I think people don’t arrive on time, so there’s a lot of bleacher that shows through. Still looks fairly bright to me. The sun is on those empty seats and some white shirts.
He’s complaining about the PRE-GAME WARM UP conditions. Seems somewhat less than compelling.
And the first inning. Which I studied.
Looking at the picture, I don’t see a mass of white that would affect the hitter, unless if the pitcher is right-handed and throwing from a three quarters slot. Mostly I see the green background from the scoreboard area. But I’ve never stood in that batter’s box (been a long time since I’ve been in any batter’s box, and I’ve never hit in a park with bleacher stands), perhaps that is more distracting than I can imagine from the picture.
So what I’m getting from all this is Giants fans in the bleachers should wear a white shirt underneath a dark windbreaker, and take off the windbreaker when the opposing team is up, and put it back on when the Giants are up. :^)
“So the Giants have the largest first-inning home-field advantage in baseball. ”
That, or they have had some of the best setup men in baseball for the past 15 years.
It’s cumulative scoring by the end of the eighth, but that is a good point. Because of park factors, though, I couldn’t go with raw scoring.
Oh, well you should be more specific about that in the article. I too was thinking you were just comparing the first inning to the 8th inning while ignoring innings 2 through 7.
I am not sure if I’d buy that, because it seems like such a tiny difference, and I don’t know the variability. Maybe you can also compute the between-year standard deviation.
What do you make of the Brewers and Orioles being such outliers at the other end of the first table?
There are at least two ways of spinning the ratio– either the Giants are the best in the first or worst after the first. Yet, another possible reason is that their pitchers become less effective more quickly than other staffs. Clearly some absolute numbers are needed to make the ratios more informative.
15 years is a lot of different staffs. I hoped to eliminate personnel issues this way, and would have gone back further if ATT existed longer.
The data studied only has to do with 1st inning and 8th inning, it has nothing to do with what the Giants do after the first inning.
And by the 8th inning, it is really looking more at the Giants setup relievers vs. the opponents setup relievers, so there should not be any fatigue factor as you suggest.
And the Giants setup relievers have been among the best in the majors, at least in recent years, but generally, a Sabean bullpen has been a good one, except in the years we had Benitez.
Do other parks have such a massive scoreboard over the batting eye? That, too, could be distracting.
If I were a highschool math teacher, this would be on the final exam:
AT&T Park is located at 37.7786° N, 122.3892° W. The Height of the shadow casting stadium parts are 172, 117, and 123 ft. If the sun moves across the horizon at 15 degrees per hour, use these numbers and all that SOHCAHTOA crap that I’ve spent the last 4 months trying to beat into your heads to show which months the SF Giants receive an advantage by starting the game at 7:15. On June 24th, the sun has an altitude of 64.4 degrees at 7:15pm.
In your answer, please reference table a, which shows the percent of runs per inning in the NL.
Any guesses as to why the Orioles have been so much worse in day games, and their opponents so much better? It’s the biggest difference in either direction, and significantly bigger than the next biggest. Would love to see some further investigation.